The goal of this study is to follow renal function in a group of psoriasis patients who received cyclosporine for up to three years. Cyclosporine treatment was associated with progressive renal interstitial fibrosis and a small decline in glomerular filtration rate (FGR, measured as iothalamate clearance). Cyclosporine has been stopped and we are continuing to perform serial measurements of GFR for up to three additional years to determine if renal function stabilizes, improves, or declines further.